By the early 1990s, Kowloon Walled City in Hong Kong was the densest place in the world with 50,000 people packed into its 2.6 hectare area. The city was demolished in 1993 but not before a group of Japanese researchers, under the leadership of cultural anthropologist Hiroaki Kani, undertook the marathon task of documenting its hive-like interior. The result of their survey was a book (sadly only in Japanese) containing this mind-bogglingly detailed cross-section illustration by Kazumi Terasawa. Take a look at our exploration of the drawing; ten points for those who spot the handstander, the “gentlemen’s club” and the small figure relieving himself from a rooftop. p(gk)